Drum dryer for laundry

ABSTRACT

A drum dryer for laundry, consisting of an inner drum with a perforated inner drum jacket rotatably mounted in a stationary housing, a heating unit for heating the air conducted into the inner drum and an outer drum surrounding this inner drum, the inner surface of which outer drum is cooled by a liquid in order to condense the steam emanating from the inner drum. The outer drum likewise executes a rotary movement, and the cooling fluid is conducted by means of a feed line directly into the annular space formed between the inner drum and the outer drum.

United States Patent [151 3,651,580 Meyer [45] Mar. 28, 1972 [54] DRUM DRYER FOR LAUNDRY [72] Inventor: Anfried Meyer, Neckargartacherstrasse,

7101 Frankenbach, Germany 22 Filed: on. 20, 1969 571 ABSTRACT [21] App]. No.: 867,446 A drum dryer for laundry, consisting of an inner drum with a perforated inner drum jacket rotatably mounted in a stationary housing, a heating unit for heating the air conducted into I Primary Examiner--Edward J. Michael Attorney-Craig, Antonelli & Hill U.S.Cl ..34/l33 the inner drum and an outer drum Surrounding his inner drum. the inner surface of which outer drum is cooled by u [58] Field of Search ..34/133, 134, 137 liquid in order to condense the Steam emanating from the inner drum. The outer drum likewise executes a rotary move- [56] References Cited ment, and the cooling fluid is conducted by means of a feed UNITED STATES PATENTS line directly into the annular space formed between the inner drum and the outer drum.

2,644,245 7/1953 Hammell ..34/l33X 2,925,663 2/1960 Smith ..34/l33X l5CIaims,3DrawingFigures Patented March 28, 1972 3,651,580

2 Sheets-Sheet 1 Fig.1

Patented March 28, 1972 2 Sheets-Sheet 2 Fig. 2

DRUM DRYER FOR LAUNDRY BACKGROUND OF THE INVENTION The present invention relates to a drum dryer for laundry, and more particularly, to a drum dryer consisting of a driven inner drum with a perforated inner drum jacket or wall rotatably mounted in a housing, a heating unit for heating the laundry disposed in the inner drum and an outer drum surrounding the inner drum and cooled by cooling fluid on the inner surface for condensing the steam emanating from the inner drum.

Drurn dryers for laundry of the aforementioned type are known wherein the inner drum is disposed in a stationary outer drum. Cooling fluid is conducted laterally into the space surrounding the inner drum, approximately at the level of the drum axis and runs downwardly along the inner side, thus cooling this area. Since the cooling fluid is to wet only the inner surface of the outer drum, the feed for the cooling fluid can be disposed, at most, at the level of the drum axis, that is, the outer drum, with the aid of two cooling liquid feed lines, can only be cooled to approximately one-half thereof.

During the drying process, small particles, so-called lint particles, are continuously detached from the laundry, entrained by the air current and deposited within the machine in various uncontrollable, as well as difficult-to-reach, places or on special lint screens. These settled lint particles must be removed from time to time in order to maintain the operability of the machine. Since the annular space between the outer drum and the inner drum is relatively narrow and, furthermore, since there is another interspace between the rear end walls of the two drums wherein the lint particles can settle, the removal of lint in this conventional dryer represents a considerable expenditure in work and time. On the other hand, the relatively small condensing surface results in a relatively long drying time. British Pat. No. 803,337 and U.S. Pat. No. 2,833,056 show such conventional dryers.

Furthermore, a drum washing and drying machine wherein the drum consists of an outer drum fixedly connected with a perforated inner drum are also known. The rear wall of the outer drum is charged with cooling fluid and thus serves as the condensing surface for the steam emanating from the inner drum. This steam, after exiting from the inner drum, flows .through the annular space formed between the two drums and then flows radially inwardly between the two drum end walls and to the outside through an axial annular space. Heating is effected through the hollow drum shaft or axle with the aid of a heating unit disposed on the outside. In this machine, lint particles can likewise adhere to places which are accessible only with difficulty, namely on the inner side of the outer drum jacket, as well as on the outside of the rear wall of the inner drum. Finally, the drain pipe for the washing liquid or the cooling and condensation liquid which dips into a collecting channel or trough formed by the outer drum can pick up only a fraction of the'rinsed-off lint particles. The remainder is left in the machine and must be removed in a complicated operating step. In addition, the condensing surface is also relatively small in this dryer, and thus the drying efficiency is relatively minor. Therefore, this machine as shown, for example, in U.S. Pat. No. 2,925,663 likewise exhibits the conventional disadvantages and cannot be employed solely as a dryer.

SUMMARY OF THE INVENTION It is the aim of the present invention to provide a drum dryer which overcomes the problems and disadvantages of the prior art.

Accordingly, the present invention is based on the problem of facilitating the removal of the lint particles, as well as increasing the degree of efficiency of such a dryer.

The underlying problems are solved in accordance with the present invention, by providing that the outer drum executes a rotary motion and that, for the introduction of the cooling fluid, a feed line is arranged which terminates in the annular space formed between the inner drum and the outer drum.

A particularly simple and practical embodiment is obtained, according to a further development of the invention, by the provision that the heating elements of the heating unit extend into the annular space, and the feed line for the cooling fluid, constructed as a feed pipe, likewise extends into this annular space. In this connection, the feed pipe, as seen in the direction of rotation of the outer drum, is disposed closely behind the heating elements, and the spraying or sparging direction of the cooling fluid is preferably oriented in the direction of rotation of the outer drum.

Accordingly, it is an object of the present invention to provide a drum dryer wherein the removal of lint is facilitated.

It is a further object of the present invention to provide a drum dryer with increased efficiency.

It is a still further object of the present invention to provide a drum dryer of simple and economical construction.

BRIEF DESCRIPTION OF THE DRAWINGS These and further objects, features and advantages will become more apparent from the following description when taken in connection with the following drawings which show, for purposes of illustration only, several embodiments in accordance with the present invention, and wherein:

FIG. 1 is a longitudinal sectional view of the drum dryer along line Il of FIG. 2;

FIG. 2 is a sectional view along line II-ll of FIG. 1; and

FIG. 3 is a longitudinal sectional view of a still further embodiment of the drum dryer in accordance with the present invention.

DETAILED DESCRIPTION OF THE DRAWINGS Referring now to the drawings and, in particular, to FIGS, 1 and 2, the drum dryer is provided with a housing 1 wherein an inner drum 4 is rotatably mounted on an axle or shaft 3 attached to the rear wall 2 of the housing. The jacket or wall 5 of this inner drum 4 is perforated and carries several entrainer or follower ribs 6 on its inner side and distributed over the circumference thereof. The end wall 7 of the inner drum 4, which is disposed opposite to the axle 3, is equipped with a charging and removal aperture 8 which can be closed by a door 9 hingedly connected to the front wall 26 of the housing 1.

The inner drum 4 is surrounded by an outer drum 10 consisting of an unperforated outer drum jacket 11 and an end wall 12 which is rigidly connected with the inner drum 4. The end wall 12 is disposed on the side of the charging and removal aperture 8, so that the annular space 13 present between the inner drum jacket 5 and the outer drum jacket 11 is thus open toward the rear. Heating elements 14, in the shape, for example, of electrically heated bars or coils, which are attached to the rear wall 2 of the housing I, extend into this annular space 13. Preferably ,these heating elements 14 extend substantially over along the entire longitudinal area of the inner drum 4 and are mounted in the upper peripheral range of the annular space 13. Reflector surfaces 15, which extend between the outer drum jacket 11 and the heating elements l4 and are likewise attached to the rear wall 2, serve for reflecting the heat exclusively onto the inner drum 4 and thus on the laundry contained therein.

As seen in the direction of rotation of the drums 4, 10, a feed pipe 16 extends behind the heating elements 14, in the proximity thereof, into the annular space 13 and continues substantially over the entire longitudinal extension thereof. This feed pipe 16 is in communication with a pressure line for a cooling fluid and is provided with, in the area of the drums 4, 10, a series of radial bores 17 through which the exiting cooling medium is sprayed or sparged in the direction of rotation of the outer drum 10 onto the inner surface of the latter. By the rotatory movement of the outer drum 10, the entire inner surface of the outer drum jacket 11 is constantly covered with a film of cooling fluid and is cooled thereby. The excess cooling fluid is discharged from the rearward opening of the annular space 13 and enters a collecting channel 18 extending along the circumference of the drum. At the deepest point of this collecting channel, a drain pipe 19 is connected which leads to the outside. In the zone of the drain pipe 19, a lint separator and/or a feed pump can be provided. For the rotary drive of drums 4, 10, a motor 20 is provided with a V-belt 21 extending around the outer drum 10.

In order to prevent spreading of the steam and thus the deposition of lint in the entire machine, the drums 4, 10 are sealed with respect to the housing 1. A tight seal of the charging and removal aperture 8 is obtained by a sealing plate 22 which, in the locked position, contacts the rim of the charging and removal aperture 8 by means of a gasket 23. This plate is under the force ofa spring 24. The sealing plate 22 is rotatably mounted at the door 9 in such a manner that it can yield radially and axially in order to be able to follow the movements of the drum in this manner. The rear end of the drums 4, 10 carries a continuous gasket ring 25 placed around the outside, which contacts a sealing surface attached to the housing. Preferably, a sidewall and/or the bottom surface of the collecting channel 18 is employed as the sealing surface.

It can be seen that the laundry introduced into the inner drum 4 is heated by the heating elements 14 and the liquid still contained in the laundry is evaporated in this manner. Due to the motions of the drums 4, 10 as well as the laundry contained therein, an intensive air circulation takes place, which causes the steam to exit from the perforated inner drum 4 and come into contact with the cooled inner surface of the outer drum jacket I1. Because of the condensation effect, the liquid is deposited and is discharged, together with the cooling fluid, through the drain pipe 19. In the same manner, the lint particlcs removed from the laundry pass from the inner drum 4 into the cooling fluid and are likewise discharged constantly to the outside together with the cooling fluid.

It is, of course, also possible to construct the outer drum 10 as a separate drum having its own bearing and being equipped with an independent rotary drive. Thereby, it is possible to set a constant speed of rotation and direction of rotation for the outer drum designed for an optimum condensation effect, while the inner drum 4 is driven at a higher or lower speed of rotation as required and/or with a reversing direction of rotation. The electrically powered heating elements 14 can furthermore be replaced by pipes through which steam, hot water, or hot oil is conducted. Depending upon the requirements, it is also possible to provide several feed pipes 16 for the cooling fluid, perhaps with differing spraying directions or with different quantities ofliquid being sprayed therefrom.

According to FIG. 3, the drums 4, 10 can also be mounted on friction wheels or gears 27 driven by the motor 20. In this connection, the drum rear wall is equipped with an opening 28 for the introduction of hot air into the inner drum 4. By means of a blower 29, a closed air cycle is produced which continuously absorbs evaporated liquid in the inner drum 4 and passes it on to the cooled jacket 11 of the outer drum. For heating purposes, a radiator is provided behind the blower 29. The air circulation is indicated by directional arrows. The blower 29 and the radiator 30 are screened or protected from the lint particles by a conical extension 31 of the drum and a sealing ring 32. It is further possible to utilize the warm cooling water emanating from the drum dryer for an additional purpose such as, for example, in one or several washing machines disposed thereafter, the water feed of which is in communication with the drain pipe 19, optionally with the interposition of a collecting tank. The lint particles contained in the cooling water are collected in a conventional manner prior to further use of the water and can be removed with few manipulations. The feed pipe 16 can also be introduced coaxially to the drums 4, l0 and can be extended to the annular space 13 by way of a radial connecting piece. Finally, the feed pipe 16 can be extended into the annular space 13 over only part of the longitudinal area or not at all. In this manner, reinforcements can be additionally provided between the outer drum and the inner drum. Finally, the feed pipe 16 can also be mounted to be rotatable together with the drums 4, 10.

The advantages attained by means of the present invention reside, in particular, in that it is possible to simultaneously collect by means of the cooling fluid, the lint particles exiting from the inner drum, and to convey these lint particles to the outside. Accordingly, a continuous removal of lint takes place already during the drying process so that any clogging and the periodic removal of the collected lint particles are completely eliminated. Consequently, a considerable facilitation of the work involved, as well as a uniform operation of the drum dryer, are attained. Moreover, the cooling fluid cools the inner surface of the outer drum along the entire circumference thereof. The cooling area is thus very large and can condense substantial amounts of evaporated liquid. Therefore, the drum dryer of this invention not only poses merely minor requirements regarding the maintenance thereof, but also operates at a higher degree of efficiency than conventional drum dryers.

While I have shown and described herein only several embodiments in accordance with the present invention, it is understood that the same is susceptible of numerous changes and modifications as to a person skilled in the art, and I, therefore, do not wish to be limited to the details shown and described herein but intend to cover all such changes and modifications that are within the scope of the present invention.

I claim:

1. Drum dryer for laundry comprising a housing; a driven inner drum having a perforated inner drum jacket rotatably mounted in said housing; heating means for heating laundry disposed within said inner drum; an outer drum surrounding said inner drum and being rotatable with respect to said housing; cooling fluid for cooling the inner circumferential surface of said outer drum for condensing the steam emanating from said inner drum; and feed line means terminating in an annular space formed between said inner drum and said outer drum for applying said cooling fluid to substantially the entire inner circumferential surface of said outer drum, wherein said heating means include heating elements, said heating elements and said feed line means extending into said annular space.

2. Drum dryer according to claim 1, wherein said feed line means is a feed pipe which, as viewed in the direction of rotation of said outer drum, is disposed closely behind said heating elements.

3. Drum dryer according to claim 1, wherein said feed line means is a feed pipe which, as viewed in the direction of rotation of said outer drum, is disposed closely behind said heating elements, said cooling fluid being sprayed substantially in the direction of rotation of said outer drum, and wherein said outer drum is fixedly connected with said inner drum for rotation therewith.

4. Drum dryer according to claim 3, further including reflection means located between said heating means and the jacket of said outer drum within said annular space for directing heat radiation onto said inner drum.

5. Drum dryer according to claim 4, wherein a collecting channel is associated with said housing, said collecting channel being disposed along the circumference of one annular opening ofsaid annular space.

6. Drum dryer according to claim 5, including a charging and removal aperture in said housing, a door mounted on said housing for closing said aperture and being provided with a sealing plate which is rotatably mounted as well as axially and radially resilient, means for selectively locking said sealing plate, and a gasket associated with said aperture, whereby when said sealing plate is in the locked position, said sealing plate along with said gasket contacts the rim of said charging and removal aperture.

7. Drum dryer according to claim 6, further including reflection means located between said heating means and the jacket of said outer drum within said annular space for directing heat radiation onto said inner drum.

8. Drum dryer for laundry comprising a housing; a driven inner drum having a perforated inner drum jacket rotatably mounted in said housing; heating means for heating laundry disposed within said inner drum; an outer drum surrounding said inner drum and being rotatable with respect to said housing; cooling fluid for cooling the inner circumferential surface of said outer drum for condensing the steam emanating from said inner drum; and feed line means terminating in an annular space formed between said inner drum and said outer drum for applying said cooling fluid to substantially the entire inner circumferential surface of said outer drum, further including reflection means located between said heating means and the jacket of said outer drum within said annular space for directing heat radiation onto said inner drum.

9. Drum dryer for laundry comprising a housing; a driven inner drum having a perforated inner drum jacket rotatably mounted in said housing; heating means for heating laundry disposed within said inner drum; an outer drum surrounding said inner drum and being rotatable with respect to said housing; cooling fluid for cooling the inner circumferential surface of said outer drum for condensing the steam emanating from said inner drum; and feed line means terminating in an annular space formed between said inner drum and said outer drum for applying said cooling fluid to substantially the entire inner circumferential surface of said outer drum, wherein a collecting channel is associated with said housing, said collecting channel being disposed along the circumference of one annular opening of said annular space, and wherein said outer drum is provided with a sealing ring at the rear end thereof, said sealing ring sealingly contacting a surface of said collecting channelv 10. Drum dryer according to claim 9, wherein said outer drum is operatively mounted and driven independently of said inner drum.

11. Drum dryer according to claim 10, wherein said outer drum is provided with a sealing ring at the rear end thereof, said sealing ring sealingly contacting a surface of said collecting channel.

12. Drum dryer according to claim 9, and further including blower means providedwithin said housing for producing air flow through said inner drum.

13. Drum dryer for laundry comprising a housing; a driven inner drum having a perforated inner drum jacket rotatably mounted in said housing; heating means for heating laundry disposed within said inner drum; an outer drum surrounding said inner drum and being rotatable with respect to said housing; cooling fluid for cooling the inner circumferential surface of said outer drum for condensing the steam emanating from said inner drum; and feed line means terminating in an annular space formed between said inner drum and said outer drum for applying said cooling fluid to substantially the entire inner circumferential surface of said outer drum, including a charging and removal aperture in said housing, a door mounted on said housing for closing said aperture and being provided with a sealing plate which is rotatably mounted as well as axially and radially resilient, means for selectively locking said sealing plate, and a gasket associated with said aperture, whereby when said sealing plate is in the locked position, said sealing plate along with said gasket contacts the rim of said charging and removal aperture.

14. Drum dryer according to claim 13, wherein said outer drum is provided with a sealing ring at the rear end thereof, said sealing ring sealingly contacting a sidewall and/or the bottom surface of said collecting channel.

15. Drum dryer for laundry comprising a housing; a driven inner drum having a perforated inner drum jacket rotatably mounted in said housing; heating means for heating laundry disposed within said inner drum; an outer drum surrounding said inner drum and being rotatable with respect to said housing; cooling fluid for cooling the inner circumferential surface of said outer drum for condensing the steam emanating from said inner drum; and feed line means terminating in an annular space formed between said inner drum and said outer drum for applying said cooling fluid to substantially the entire inner circumferential surface of said outer drum, wherein said outer drum is operatively mounted and driven independently of said inner drum. 

1. Drum dryer for laundry comprising a housing; a driven inner drum having a perforated inner drum jacket rotatably mounted in said housing; heating means for heating laundry disposed within said inner drum; an outer drum surrounding said inner drum and being rotatable with respect to said housing; cooling fluid for cooling the inner circumferential surface of said outer drum for condensing the steam emanating from said inner drum; and feed line means terminating in an annular space formed between said inner drum and said outer drum for applying said cooling fluid to substantially the entire inner circumferential surface of said outer drum, wherein said heating means include heating elements, said heating elements and said feed line means extending into said annular space.
 2. Drum dryer according to claim 1, wherein said feed line means is a feed pipe which, as viewed in the direction of rotation of said outer drum, is disposed closely behind said heating elements.
 3. Drum dryer according to claim 1, wherein Said feed line means is a feed pipe which, as viewed in the direction of rotation of said outer drum, is disposed closely behind said heating elements, said cooling fluid being sprayed substantially in the direction of rotation of said outer drum, and wherein said outer drum is fixedly connected with said inner drum for rotation therewith.
 4. Drum dryer according to claim 3, further including reflection means located between said heating means and the jacket of said outer drum within said annular space for directing heat radiation onto said inner drum.
 5. Drum dryer according to claim 4, wherein a collecting channel is associated with said housing, said collecting channel being disposed along the circumference of one annular opening of said annular space.
 6. Drum dryer according to claim 5, including a charging and removal aperture in said housing, a door mounted on said housing for closing said aperture and being provided with a sealing plate which is rotatably mounted as well as axially and radially resilient, means for selectively locking said sealing plate, and a gasket associated with said aperture, whereby when said sealing plate is in the locked position, said sealing plate along with said gasket contacts the rim of said charging and removal aperture.
 7. Drum dryer according to claim 6, further including reflection means located between said heating means and the jacket of said outer drum within said annular space for directing heat radiation onto said inner drum.
 8. Drum dryer for laundry comprising a housing; a driven inner drum having a perforated inner drum jacket rotatably mounted in said housing; heating means for heating laundry disposed within said inner drum; an outer drum surrounding said inner drum and being rotatable with respect to said housing; cooling fluid for cooling the inner circumferential surface of said outer drum for condensing the steam emanating from said inner drum; and feed line means terminating in an annular space formed between said inner drum and said outer drum for applying said cooling fluid to substantially the entire inner circumferential surface of said outer drum, further including reflection means located between said heating means and the jacket of said outer drum within said annular space for directing heat radiation onto said inner drum.
 9. Drum dryer for laundry comprising a housing; a driven inner drum having a perforated inner drum jacket rotatably mounted in said housing; heating means for heating laundry disposed within said inner drum; an outer drum surrounding said inner drum and being rotatable with respect to said housing; cooling fluid for cooling the inner circumferential surface of said outer drum for condensing the steam emanating from said inner drum; and feed line means terminating in an annular space formed between said inner drum and said outer drum for applying said cooling fluid to substantially the entire inner circumferential surface of said outer drum, wherein a collecting channel is associated with said housing, said collecting channel being disposed along the circumference of one annular opening of said annular space, and wherein said outer drum is provided with a sealing ring at the rear end thereof, said sealing ring sealingly contacting a surface of said collecting channel.
 10. Drum dryer according to claim 9, wherein said outer drum is operatively mounted and driven independently of said inner drum.
 11. Drum dryer according to claim 10, wherein said outer drum is provided with a sealing ring at the rear end thereof, said sealing ring sealingly contacting a surface of said collecting channel.
 12. Drum dryer according to claim 9, and further including blower means provided within said housing for producing air flow through said inner drum.
 13. Drum dryer for laundry comprising a housing; a driven inner drum having a perforated inner drum jacket rotatably mounted in said housing; heating means for heating laundry disposed within said inner drum; an outer drum surrounding saId inner drum and being rotatable with respect to said housing; cooling fluid for cooling the inner circumferential surface of said outer drum for condensing the steam emanating from said inner drum; and feed line means terminating in an annular space formed between said inner drum and said outer drum for applying said cooling fluid to substantially the entire inner circumferential surface of said outer drum, including a charging and removal aperture in said housing, a door mounted on said housing for closing said aperture and being provided with a sealing plate which is rotatably mounted as well as axially and radially resilient, means for selectively locking said sealing plate, and a gasket associated with said aperture, whereby when said sealing plate is in the locked position, said sealing plate along with said gasket contacts the rim of said charging and removal aperture.
 14. Drum dryer according to claim 13, wherein said outer drum is provided with a sealing ring at the rear end thereof, said sealing ring sealingly contacting a sidewall and/or the bottom surface of said collecting channel.
 15. Drum dryer for laundry comprising a housing; a driven inner drum having a perforated inner drum jacket rotatably mounted in said housing; heating means for heating laundry disposed within said inner drum; an outer drum surrounding said inner drum and being rotatable with respect to said housing; cooling fluid for cooling the inner circumferential surface of said outer drum for condensing the steam emanating from said inner drum; and feed line means terminating in an annular space formed between said inner drum and said outer drum for applying said cooling fluid to substantially the entire inner circumferential surface of said outer drum, wherein said outer drum is operatively mounted and driven independently of said inner drum. 